Development of Advanced Chemometric-Assisted Spectrophotometric Methods for the Determination of Cromolyn Sodium and Its Alkaline Degradation Products.

Advanced and sensitive spectrophotometric and chemometric analytical methods were successfully established for the stability-indicating assay of cromolyn sodium (CS) and its alkaline degradation products (Deg1 and Deg2). Spectrophotometric mean centering ratio spectra method (MCR) and chemometric methods, including principal component regression (PCR) and partial least square (PLS-2) methods, were applied. Peak amplitudes after MCR at 367.8 nm, 373.8 nm and 310.6 nm were used within linear concentration ranges of 2-40 µg mL-1, 5-40 µg mL-1 and 10-100 µg mL-1 for CS, Deg1 and Deg2, respectively. For PCR and PLS-2 models, a calibration set of eighteen mixtures and a validation set of seven mixtures were built for the simultaneous determination of CS, Deg1 and Deg2 in the ranges of 5-13 µg mL-1, 8-16 µg mL-1, and 10-30 µg mL-1, respectively. The authors emphasize the importance of a stability-indicating strategy for the investigation of pharmaceutical products.

Simultaneous Determination of Cromolyn Sodium Combined Dosage Forms Using Isocratic HPLC Method.

A simple and selective reversed-phase high-performance liquid chromatography method was developed for the estimation of cromolyn sodium (CRM) with either oxymetazoline hydrochloride (OMZ) or xylometazoline hydrochloride (XMZ) in their binary mixtures. The method is based on the simultaneous separation of each drug in a reversed-phase Waters symmetry® C18 column (250 mm × 4.6 mm intradermally, 5-µm particle size) at 25°C. Elution was performed with a mobile phase consisting of methanol : 0.1 M phosphate buffer (60:40, v/v, pH 4.0). Quantitation was achieved with ultraviolet detection at 220 nm. The method could determine the three drugs, with linearity, in the range of 2.0-100.0 µg/mL for CRM and 0.8-8.0 µg/mL for OMZ and for XMZ. Aspirin was used as internal standard. Optimization of the separation in terms of mobile phase composition is critical to the method development, which is discussed in detail. The suggested procedure was successfully applied to the analysis of the studied drugs in their nasal preparations. Statistical evaluation of the data obtained by the proposed and comparison methods revealed good accuracy of the proposed method.

Development and validation of impurity-profiling UPLC method for the determination of sodium cromoglicate and tetryzoline hydrochloride: Application on rabbit aqueous humor.

Sodium cromoglicate (SCG), antihistaminic agent, and tetryzoline hydrochloride (TZH), a sympathomimetic agent, are formulated together as an ophthalmic preparation. An ultra-performance liquid chromatographic method with UV detection (UPLC-UV) was developed and validated for the quantitative determination of SCG and TZH in rabbit aqueous humor. Due to the instability of both SCG and TZH under alkaline conditions, the UPLC method was applied for their determination in the presence of their possible degradation impurities. The separation was performed using C18 column (1.7µm particle size) and isocratic elution system with methanol: 1% o-phosphoric acid (65: 35, v/v).The optimum flow rate was 0.5ml/min and the detection was done at 230nm. The suggested method was validated in compliance with the ICH guidelines and was successfully applied for determination of sodium cromoglicate (SCG) and tetryzoline HCl (TZH) as prepared synthetically in laboratory mixtures, and in the presence of their alkali-induced degradation impurities. The suggested method was effectively applied the determination of spiked rabbit aqueous humor samples as well as commercial pharmaceutical formulation.

Sensitive detection of sodium cromoglycate with glutathione-capped CdTe quantum dots as a novel fluorescence probe.

A sensitive and simple analytical strategy for the detection of sodium cromoglycate (SCG) has been established based on a readily detectable fluorescence quenching effect of SCG for glutathione-capped (GSH-capped) CdTe quantum dots (QDs). The fluorescence of GSH-capped CdTe QDs could be efficiently quenched by SCG through electron transfer from GSH-capped CdTe QDs to SCG. Under optimum conditions, the response was linearly proportional to the concentration of SCG between 0.6419 and 100 µg/mL, with a correlation coefficient (R) of 0.9964; the detection limit (3δ/K) was 0.1926 µg/mL. The optimum conditions and the influence of coexisting foreign substances on the reaction were also investigated. The very effective and simple method reported here has been successfully applied to the determination of SCG in synthetic and real samples. It is believed that the established approach could have good prospects for application in the fields of clinical diseases diagnosis and treatment.

Novel spectroscopic methods for determination of Cromolyn sodium and Oxymetazoline hydrochloride in binary mixture.

New accurate, sensitive and selective spectrophotometric and spectrofluorimetric methods were developed and subsequently validated for determination of Cromolyn sodium (CS) and Oxymetazoline HCl (OXY) in binary mixture. These methods include 'H-point standard addition method (HPSAM) and area under the curve (AUC)' spectrophotometric method and first derivative synchronous fluorescence spectroscopic (FDSFS) method. For spectrophotometric methods, absorbances were recorded at 241.5nm and 274.9nm for HPSAM and the wavelength was selected in ranges 232.0-254.0nm and 216.0-229.0nm for AUC method, where the concentration was obtained by applying Cramer's rule. For FDSFS method, the first-derivative synchronous fluorescence signal was measured at 290.0nm, using Δλ=145.0nm. The suggested methods were validated according to International Conference of Harmonization (ICH) guidelines and the results revealed that they were precise and reproducible. All the obtained results were statistically compared with those of the reported method and there was no significant difference.

Development of a rapid and automatic optosensor for the determination of cromolyn in biological samples.

Disodium cromoglycate (SCG) is an anti-allergic drug, which is applied locally or inhaled. After administration, a very small portion of the drug is absorbed, being the most eliminated part unchanged in the urine and bile; therefore, its determination in urine is indicative of the dose absorbed. Here, the first spectroscopic method for the determination of SCG, making use of a sequential injection optosensor with terbium-sensitized luminescence detection, is described. The cationic resin Chelex-100 was used as solid support in the detection area. The measurements were made at 336/545 nm (lambda(ex)/lambda(em)) and the system was calibrated for two sample volumes, 150 and 800 microl, depending on the samples analyzed. A detection limit of 15 ng ml(-1) and a RSD lower than 2% (n=10) were observed using the highest sample volume. The proposed method does not use any organic solvent or surfactant, so being environmental friendly. The analyte was satisfactorily determined in pharmaceuticals and human urine, the latter being spiked at the concentrations found after the administration of the drug.

Stability-indicating assay of sodium cromoglicate in ophthalmic solution using mixed-mode hydrophilic interaction chromatography.

A hydrophilic interaction chromatographic (HILIC) procedure for the quantification of Sodium Cromoglicate (SCG) in ophthalmic solution is developed. Mobile phase consists of ACN and buffer, 86:14 v/v. Atlantis HILIC-Si column, 25 cm x 4.6 mm, is used as stationary phase. Detection is carried out using a variable wavelength UV-Vis detector at 326 nm. Linearity range and percent recoveries for SCG were 50-400 mug/mL and 100.44%, respectively. The SCG HILIC-UV assay was validated according to the International Conference on Harmonization guidelines. The method separates two impurities and degradation products resulting from stress environment. Influence of organic solvent, ionic strength and mobile phase pH on the retention of SCG is studied. The paper provides optimization of polar anionic solute (SCG) on unmodified silica by HILIC. Proposed method can be used as a stability-indicating assay for SGC and can be proved to be beneficial in ESI-MS for enhanced sensitivity.

Quantitative determination of drug encapsulation in poly(lactic acid) nanoparticles by capillary electrophoresis.

Capillary electrophoretic (CE) methods were used for the quantitative determination of model drugs [salbutamol sulphate (SS), sodium cromoglycate (SCG) and beclomethasone dipropionate (BDP)] in poly(D,L-lactic acid) (PLA) nanoparticles, which were prepared by the nanoprecipitation method. Zeta potential and size distribution of the nanoparticles were determined by electrophoretic mobility determinations and photon correlation spectroscopy, respectively. Interactions between the drugs, the PLA nanoparticles and the fused-silica capillary were investigated by electrokinetic capillary chromatography (EKC). A quantitative CE method was developed for salbutamol sulphate and sodium cromoglycate, and the linearity and repeatability of migration times, peak areas and peak heights were determined. Microemulsion electrokinetic chromatography was used for the quantitative determination of beclomethasone dipropionate. According to this study, the applied electromigration techniques were suitable for the interaction, drug entrapment and dissolution studies of pharmaceutical nanoparticles. The results suggest that even quantitation of the drug located inside the nanoparticles was possible. Encapsulation of the more hydrophilic model drugs (SS, SCG) in the PLA nanoparticles was less efficient than in the case of BDP.

Hyphenation of Raman spectroscopy with gravimetric analysis to interrogate water-solid interactions in pharmaceutical systems.

A moisture sorption gravimetric analyzer has been combined with a Raman spectrometer to better understand the various modes of water-solid interactions relevant to pharmaceutical systems. A commercial automated moisture sorption balance was modified to allow non-contact monitoring of the sample properties by interfacing a Raman probe with the sample holder. This hybrid instrument allows for gravimetric and spectroscopic changes to be monitored simultaneously. The utility of this instrument was demonstrated by investigating different types of water-solid interactions including stoichiometric and non-stoichiometric hydrate formation, deliquescence, amorphous-crystalline transformation, and capillary condensation. In each of the model systems, sulfaguanidine, cromolyn sodium, ranitidine HCl, amorphous sucrose and silica gel, spectroscopic changes were observed during the time course of the moisture sorption profile. Analysis of spectroscopic data provided information about the origin of the observed changes in moisture content as a function of relative humidity. Furthermore, multivariate data analysis techniques were employed as a means of processing the spectroscopic data. Principle components analysis was found to be useful to aid in data processing, handling and interpretation of the spectral changes that occurred during the time course of the moisture sorption profile.

In vitro deposition of the respirable fraction of dry powder inhalations determined by laser diffractometry and inertial impaction.

Particle size analysis of drug and excipient is of particular interest for dry powder inhalation (DPI) formulations development and quality control. In this work, the deposition in the upper, the medium and the lower (i.e. the respirable fraction) Twin Impinger compartments of sodium cromoglycate (SCG), lactose (as excipient) and a 1:1 mixture thereof was determined by chemical analysis using a DPI device--the Micro-hale--and compared with the results obtained by laser diffractometry for the same fractions. The analytical method for the SCG determination consisted of ultraviolet spectrophotometry and, for the lactose, high performance liquid chromatography with refractive index detection was used. Laser diffractometry as a quickly operating routine method can substitute the chemical analysis in order to evaluate the respirable fraction, under the conditions of the present work and therefore making formulation development easier and quicker.

[Color reactions for identification of sodium cromoglycate]. / Farbreaktionen zur Identitätsprüfung von Natriumcromoglicat.

Chromone-2-carboxylic acid (3) reacts with aminopyrazolone (2) in methanolic hydrochloric acid to yield the orange-red polymethine dye 4. Treating dimethyl cromoglicate (6) with compound 2 and perchloric acid leads to the tetraperchlorate 7 of the red azamerocyanine 8. The phenol 9, obtained from alkaline hydrolysis of sodium cromoglicate (1a), couples with diazotized sulfanilic acid to form the red azo dye 10. The chromone 6 condenses with 1,3-dimethylbarbituric acid (DMBA) in acetic anhydride/acetic acid to the red oxonole 12. Cromoglicinic acid (1b) reacts under these conditions to yield the yellow polymethine dye 14, whose structure is elucidated by X-ray analysis.

Técnica analítica para el estudio de estabilidad del Cromoglicato de Sodio (Cápsulas para inhalación) / Analytical technique for the stability study of sodium chromoglycate

Se desarrolló un método analítico por cromatografía líquida de alta eficiencia para la determinación del contenido de cromoglicato de sodio en las cápsulas. La técnica desarrollada resultó ser lineal, precisa, exacta y específica, la cual fue aplicada para realizar el estudio de estabilidad acelerada y el de vida de estante. Se comprobó la estabilidad química del medicamento por un período de 2 años

Reversed-phase liquid chromatographic determination of cromolyn sodium in drug substance and select dosage forms.

This study, presented as a technical communication, describes a reversed-phase liquid chromatographic method for select commercial formulations, namely, inhalation solution, nasal solution, capsule and inhalation aerosol. Miscellaneous validation parameters are also discussed.

HPLC determination of sodium cromoglycate in pharmaceutical dosage forms.

A reversed-phase high-performance liquid chromatography (HPLC) method is described for the determination of sodium chromoglycate (SCG) in bulk drug and pharmaceutical dosage forms (capsules, solutions, gels). Aliquots were chromatographed on C18 columns using methanol: phosphate buffer (50:50 v/v) at pH 2.3 as the mobile phase. Detection was performed at 326 nm with a linear range of 0.05-0.5 microgram/ml (r = 0.9999). Recovery values ranged from 99.21 to 106.31% (N = 9). The proposed method is rapid and simple, free from interference by excipient and degradation products, and can be recommended for routine control analysis of sodium chromoglycate commercial products and magistral formulations.

Determination of sodium cromoglycate in pharmaceutical dosage forms using TLC-densitometry.

A TLC-UV densitometric method for the determination of sodium cromoglycate (SCG) in ophthalmic solutions, gels and capsules has been developed. After TLC separation of active substance on silica gel GF254 using methanol-water-ethylacetate (15:45:40 v/v/v) as the mobile phase, densitometric measurements were performed with HPTLC scanner at 254 nm. The proposed method is rapid and simple, free from interference by adjuvants and can be suggested for the routine analysis of sodium cromoglycate.

Delivery of therapeutic aerosols to intubated babies.

Delivery of drug aerosols to the lungs of ventilated neonates by metered dose inhaler and spacer (Aerochamber) and ultrasonic nebuliser (Pentasonic) was assessed using sodium cromoglycate. The mean proportion of a known intratracheal dose of sodium cromoglycate excreted in the urine of four intubated infants was 37.5%. After assuming that 38% of the sodium cromoglycate aerosol reaching the neonatal lung will be excreted in the urine, three puffs (15 mg) delivered by metered dose inhaler and spacer resulted in a pulmonary dose of 258 micrograms (1.7%, n = 7). A dose of 20 mg (4 ml) sodium cromoglycate ultrasonically nebulised over five minutes into the inspiratory limb of a standard ventilator circuit produced a pulmonary dose of 257 micrograms (1.3%, n = 7). Of two in vitro lung models assessed, a combination of filter and neonatal test lung was superior to a multistage impactor in estimating the in vivo pulmonary sodium cromoglycate dose delivered by metered dose inhaler and spacer (243 micrograms v 1740 micrograms).

Respirable form of crystals of cromoglycic acid.

Respirable crystals of cromoglycic acid (CA) were prepared by precipitation of CA with hydrochloric acid from aqueous solutions of cromolyn sodium and subsequent recrystallization from hot water or mixtures of dimethyl sulphoxide and water. The properties of the materials were established by melting point measurements, UV, IR, and NMR spectroscopy, and X-ray diffraction. Aerosols of CA were generated by nebulization of dilute CA suspensions and drying. The aerodynamic size distribution of CA in the dried aerosols was found by cascade impaction, and could be characterized by a logarithmic normal function with a mass median aerodynamic diameter (MMAD) of 0.7 micron and geometric standard deviation (sigma g) of 1.9. The likely advantages and problems of CA aerosols in the prevention of asthma are discussed.

In vitro performance of the small particle aerosol generator (SPAG-2).

The anti-viral drug ribavirin primarily used for the treatment of respiratory syncytial virus (RSV) infection in infants is delivered by continuous nebulization with the Small Particle Aerosol Generator (SPAG). Clinical data suggest that the SPAG is an efficient nebulizer for ribavirin; it is also being used for the delivery of other pulmonary agents. The efficiency of a nebulizer can be defined in large part by delivering a major proportion of its output with a particle size of 1 to 5 microns which is small enough to penetrate the tracheobronchial tree. We assessed both the quality and quantity of the SPAG aerosol cloud with the aid of a multistage liquid impinger, utilizing 2% ribavirin and 1% cromolyn sodium solutions. The aerosol of either solution had a mass median aerodynamic diamter (MMAD) of approximately 1.2 microns, and this seemed insensitive to solution strength and nebulization period. Of the solutions of ribavirin and cromolyn sodium 92.3% and 95.0%, respectively, by weight of delivered particles, had aerodynamic diameters less than 5 microns and about 70-75% of the aerosol particles had an aerodynamic diameter in the 1-5 microns range. This implies that the aerosol cloud is adequate for delivery through a ventilator circuit. Performance was maintained over long (16 hours), continuous periods of delivery. The SPAG could be useful for delivery of other respiratory drugs by continuous nebulization.

Effects of calcium chelating agents on corneal permeability.

Corneal penetration studies have been conducted in unanesthetized albino rabbits using various organic compounds representing both polar and nonpolar species. In the presence of calcium chelating agents, polar compounds generally demonstrate an increase in corneal penetration. Evidence that this corneal effect is reversible is presented. Concomitant with an increase in both corneal and aqueous humor drug levels was a decrease in drug concentration in both iris and conjunctival tissues tentatively attributed to chelation effects on vascular permeability of these tissues. EDTA, a known calcium chelator, was shown to penetrate the cornea, conjunctiva, and iris/ciliary body from a topically applied dose. The implications of this observation pertain to both toxicity effects, when EDTA is incorporated into ocular drug products for stability purposes, and novel strategems for improving ocular bioavailability of topically applied drugs.